How to create a trust and transfer assets if Will mentions it?

My grandfather wrote and registered a Will in 2024. In the Will, he mentioned that he would create a private family trust during his lifetime and identified five trustees. However, due to unforeseen medical conditions and personal reasons, he could not form the trust. He had stated that all his movable and immovable assets should be transferred to the trust. How can we proceed now to create the trust and transfer his assets to it in order to fulfil my grandfather’s intention?